I know xenforo 2.0 is still in developement, but it will probably be out in the next few months. When it comes out are you going to stay on 1.5 or upgrade to 2.0?
We aren't on XenForo 1.5. And it's impossible to give any sort of valid answer about if you are going to use something that you have no info on and have never seen.
Xenforo 1.5.9 will be the next to be released. I was checking into this when I bought my license because if 2.0 was going to be out soon I was just going to wait. They have no date for 2.0 but Chris (one of the XF Developers) says that 1.5.9 is going to be the next one they release. Here's his post: https://xenforo.com/community/threads/xenforo-2-0-discussion.79603/page-81#post-1079501
Yeah you are right, Chris said there are no plans for a 1.6. He said that they are working on 1.5.9 which will be released next. He also said that they still have some significant tasks to work on for 2.0. Significant tasks will probably mean it's going to be a while and it's not coming out soon. They announced that there will be a 2.0 version almost 2 years ago and that they were not going to rush it's release because they want it to be as good as possible. Going by that and some other comments made by the XF staff I don't anticipate it being released at least till the first part of 2017 or possibly December at the earliest. They obviously aren't in any kind of rush, which is good because I would prefer that the 2.0 be as good as possible. It would be nice if it comes out soon.
And you base that on...? I just took a look at the information about the update (1.5), and most of the stuff look rather minor. The responsive admin-interface, the improved thread-tagging, media handling etc. I'm guessing that most of the improvements are already handled by custom DP code.
Not really any concerns. Just some of the new features would be nice. There are 2 step verification improvements in 1.5. https://xenforo.com/community/forums/have-you-seen/?prefix_id=36
I've read those, and sure, two-step confirmation is fine, but not really needed on a site like DP. There shouldn't be any sensitive info on a forum account, and as long as you use strong passwords, you're quite safe, regardless of a leak of the database. The point is that the rest of the improvements seem mostly minor, and doesn't warrant an update that might break themes, plugins etc.
Two-step verification has been available on this site for years already. https://forums.digitalpoint.com/threads/new-security-features.2628318/ So you need to try again for the stuff you are wishing you had.